Pump priming system



May 25 A. G. SHEPPARD 2,347,973

PUMP PRIMING SYSTEM Filed March'Z, 1942 Patented May 2, 1944 PUMPPRIMING SYSTEM AllanlG. Sheppard, Elmira, N. Y., assignor to American-LaFrance-Foamite Corporation, Elmira, N. Y., a corporation of New YorkApplication March 2, 1942, Serial No. 433,089

7 Claims. (Cl. 103-113) The invention is an improved priming system forcentrifugal pumps such as used in motorized fire engines and whereinprecautions are necessary for preventing passage of water from thepump`to the suction mechanism by which the priming is eiected. When thesource of suction is a combustion engine, as customarily the case, orother mechanism normally intended to handle gases only, disastrousresults may ensue from the entry of water into it. Such entry may occurthrough inadvertence as by connecting the pumps intake to a source ofwater under pressure such as a hydrant, or to another iire engine,without rst closing the priming connection, in which case the hydrantpressure may iiood the engine through the priming line. Prevention ofaccident from this cause is highly important and is effectively aordedby the' present invention without any mechanical complication.

In the accompanying drawing, Fig. 1 shows the organization of theinvention in a conventional type of fire engine, parts only of whichappear, and Fig. 2 is a larger scale diagram o'f the priming lineconnections.

The centrifugal pump indicated generally at I is shown as mounted on thechassis 2 of the re engine and maybe understood to have two or moredischarge outlets 3 controlled by gates 4 and two suction intakes 5, oneon each side of the vehicle, also the usual control appurtenances whichare omitted from the gure. One or the other 'of these intakes isintended to be connected to a source ofwater supply, which may be insome cases a hydrant or another fire engine, and ln others a free bodyof water at a lower level, such as a river, pond, etc., in which lattercase priming the pump is necessary. By the application of suction to thepump casing the Water is drawn up into it through the connected intake,the other intake and the discharge gates of course being closed. j

The combustion engine isshown in outline at 8, and may be the sameengine that propels the vehicle and drives the pump, be'ing understoodto have the appropriate clutches for this purpose as customary in motorpumpers. Its exhaust pipe is indicated at 'I in the usual location andthe energy of the gas flow therein is utilized for creating the primingsuction. This is done by closing a deiiector valve 8 in the exhaust pipe'I thereby diverting some or all of the gas into an ejector 9discharging to atmosphere. The throat part of this ejector, which is theimmediate source of suction, is connected by a pipe or conduit syserablyat the spot marked I in Fig. 1. The ejector assembly can be and is shownas clamped directly on the exhaust pipe, being preferably directeddownwards, although it can be located wherever convenient. In anordinary case a jet of about diameter will do eiicient work.

The priming line between the gas ejector 9 and the pump includes aT-tting I I which is preferably another or second ejector and herein fordistinction called a water ejector. Its entryror nozzle end, marked I2,is connected through manual valve I3 and elbow I4 with the top I0 of thepump intake and its exit or recovery end I leads through alightly-loaded, swing-type check valve I6 to an escape outlet I'I,discharging to ground,

while its intermediate or throat section I8 is connected by pipe I9 andcheck valve 2U with the throat section 2| of the gas ejector 9.

The escape check valve I6 being normally closed, suction created by thegas ejector is transmitted through the parts just described to the pump,provided the priming valve I3 is opened, and thereby water can be suckediiito the pump, thus priming it, when that is required. Discharge ofwater from the gas ejector is the indication that the pump is primed. v

The valve I3 is provided with a. control handle at the operators stationas indicated at 22 and/fis supposed to be closed when the pump has beenprimed. If however this valve is open and the pump receives Water, notby suction but by the pressure of a hydrant for example, the velocity ofits ow from the pump through the fitting I I will carry it out throughthe easily opened swing check I6 discharging to ground. It will therebybe kept from entering and choking the exhaust gas ejector 9 which mightresult in stalling the engine and in the ilow of water .through theexhaust pipe into the engine cylinders.

'I'he capacity of the check-valved escape I6 is large enough so thatlittle or no water enters the suction-producing gas ejector 9 under suchcircumstances, and this eiect is made certain by constituting thefitting I I as a water ejector with its jet nozzle I8 appropriatelyrestricted. It is possible to restrict this nozzle to such degree thatthe jet velocity will be high enough to open the escape passage I6 underany water ow large enough to choke the gas ejector if admitted to thelatter, which is to say, that if the jet velocity is not suiiicient toopen the escape the volume of water then passing the nozzle will not beof such magnitude as to stop the action of the gas ejector if it shouldarrive in the latter by way of the line tem to some upper part of thepump casing, prei- ISL In an ordinary case the nozzle I8 would have acircular diameter of about 1,12 inch which is ample to transmit thesuction eect when priming. The pipe I9 is shown connected to the topconnected end drops below that at the throat 2 I,

which is possible to occur if for any reason the engine should slow downduring the priming and it thus serves to hold the priming suction atsuch times. The tting or water ejector Il with its escape outlet canobviously be connected at any point desired in a priming line to affordcertain and fool-proof protection against injury or malfunctioning ofthe suction mechanism. The priming line can be left open if desired, tobe closed only on such occasions as when water in the suction side ofthe pump is under pressure, for preventing wastage through the pipe I1at such times, particular care about closing the valve I3 being nolongernecessary.

I claim:

1. In a pump priming system having a pump and a suction source forpriming the pump and a priming line for transmitting suction from thesource to the pump including a water ejector having its entry connectedwith the pump, its recovery with an escape outlet and its throat withsaid source, and means for preventing inward flow through said outlet.

2. In a pump priming system having a pump and a combustion engineconnected to drive the pump and provided with an exhaust-gas ejectorconstituting a suction source, and a priming line for transmittingsuction from said source to the pump for priming the latter including awater jet ejector having its entry connected with the pump, itswater-jet discharging into an escape outlet and its throat sectionconnected with said suction source, and means for preventing inward flowthrough said outlet. l

3. In a pump priming system having a pump and a combustion engineconnected to drive the pump and provided with a gas ejector as a suctionsource, and a priming line for transmitting suction from said source tothe pump for priming the latter including a water ejector having itsentry connected-with the pump, its recovery with an escape outlet andits throat section with the throat section of said gas ejector.

4. In a pump priming system for re engines, the combination with a pumpand a pump-driving combustion engine provided with an exhaust-gasejector in its exhaust line as a suction source, a priming line fortransmitting suction from said source to the pump for priming the latterincluding a tting having its entry connected with .the pump, its otherend with an escape outlet and its intermediate section with the throatsection of said gas ejector.

5. In a pump priming system 'having a pump and a combustion engineprovided with an exhaust-gasejector inY its exhaust line constituting asuction source, a priming line for transmitting suction from said sourceto the pump for priming the latter including a fitting having itsentrance end connected with the pumpl its exit end connected with anescape outlet and having a conduit connecting its intermediate sectionwith said suction source, and means for preventing inward ow throughsaid conduit and said escape outlet.

6. Ina pump priming system for re engines, the combination with a pumpand a pump-driving combustion engine, an exhaust-gas ejector in itsexhaust line and operable thereby, a priming line for transmittingsuction from said gas ejector to the pump for priming the latterincluding a waterjet ejector having the entry to its jet nozzleconnected with the pump, its exit connected with an escape outlet and isthroat section with said gas ejector, and a check-valve for preventinginward ow through said outlet adapted to open under the force of the jetfrom said nozzle, the diameter of said nozzle being predetermined not tooverload the gas ejector when the jet force is incapable of opening saidcheck-valve.

7. In a pump priming system, a. pump, an exing water from the pump and acheck valve in such line closing toward the pump.

ALLAN G. SHEPPARD.

